Rain and cliff
An episode of particularly plentiful and continuous rains affects the Haute-Normandie at this end of year 2012. The muddy, naked cover at this time of year, is strongly affected by the streaming. Rivers, in charge of suspension materials, took a creamy tint and fill their minor course. The tablecloth of the little protected chalk is subjected to the effects of the pollution. As usual in the same situation, a ban on consumption of the tap water is decreed by the sanitary authorities (1, 2, 3)).
Cliffs are concerned too by this meteorology. The soil erosion increases in valleuses.
Silt which fill the roots of karstic dissolution is saturated in water. When the geometry of the conduit lends itself to it, they escape and pour at various levels of the cliff. In the case of the following photo, a ring of chalk was protected around the almost completely emptied muddy pocket.
Stratigraphical indication: the thick level of flint under the opening is the flint Seven Sisters, limit between average Coniacien and upper Coniacien.